Serve on the rocks for a refreshing summer drink. Photograph: Linda Nylind for the Guardian

This is a three-stage process. First you'll steep botanical herbs in vodka over a couple of weeks, then make a caramel and finally combine with wine to make a delicious dark vermouth. The botanicals listed here can all be purchased online (try baldwins.co.uk) or from Chinese herbalists.

You'll need a jam jar for each botanical tea, to be filled with roughly one third of botanicals to two thirds vodka. Add roughly a handful of each herb, then the vodka, screw on the lid and leave to macerate at room temperature for 2 weeks.

To make the caramel

Heat 200g caster sugar and 4 tbsp of water in a pan over a high heat. Don't stir, but swirl the caramel around to stop it burning. We recommend taking the caramel to a dark amber colour for extra depth and complexity. Heating it to somewhere between 185C and 188C will do the trick. Carefully pour a thin layer on to a silicone mat or oiled baking sheet, and leave to solidify. Once solid, break up into shards.

To make the vermouth

Add 125ml of wine to a pan and place on a low heat. Add the caramel shards and stir until totally dissolved. Allow the mixture to cool to room temperature, and then combine with the remaining wine. Next, strain each tea and return the liquid to its original jar. Measure out – using a pipette, a container and accurate scales – the amounts given below and add to the caramel/wine mixture. Taste each one as you add them, to get a sense of the different herbs.